This invention relates generally to pen-based computer systems and more particularly to an interactive method for entry and editing of script, text and drawings in a document display.
Script refers to handwritten characters and words. Text refers to typewritten characters and words and includes binary-encoded characters such as ASCII text. Drawings refers to hand drawn sketches but can also include imported drawings originally drawn by or on a machine.
Existing pen-based systems use gestures to edit exclusively script or ASCII text (i.e., not both interchangeably or simultaneously). They are limited, moreover, to gestures that by their form, context, or location can be distinguished from the data that they act upon. For instance, free-form gestures applied to ASCII text are recognizable because the ASCII exists in what can be termed a different plane. Free form gestures applied to selected script are recognizable because pen actions following a selection are assumed to be gestures OR because writing applied to a selected area is assumed to be a gesture. Free-form gestures occurring within a gesture sensitive area of the screen are easily recognized. Otherwise, prior systems require an explicit action to initiate gesture recognition especially within script such as selection of text or scrip or keyboard or similar input of a control command. One could alternatively designate a set of unique strokes to define gesture commands, but this approach requires interpretation of all strokes during script entry which is compute-intensive and virtually precludes mixing script, ASCII text and sketches.
Editing of untranslated script in existing systems is typically restricted to opening up space between characters or words, erasing characters or words, and applying enhancements to pieces of script (e.g., underline, bold, etc.). No known prior pen-based system enables script words to be word-wrapped, let alone doing it with mixed script and ASCII text. Developers have probably been reluctant to attempt script word wrap for the following reasons:
Processing strokes consumes a lot of CPU time making it difficult to provide whole screen word wrapping reflow and display in a timely manner. PA1 Strokes consume a lot of memory. PA1 A word wrapping algorithm for handwritten script is unheard of, to say nothing of one that can maintain the user's spacing of strokes (words). PA1 A technique is not available for opening space within a line of script for the user to write additional script and automatically providing more writing space as the user writes (i.e., a "moving" space). PA1 Certain pieces of information that delimit paragraphs and preserve horizontal/vertical whitespace during word wrap must somehow exist within the script document. The common approach to adding this sort of information to a document involves explicitly delimiting paragraphs and specifying whitespace, neither of which is conducive to the free flow of thoughts while writing.
Mixing ASCII and script text with graphics requires a gesture set that functions the same with both types of text and is not confused with script writing or graphics drawing. Mixing ASCII with script text in the same edit plane is not known to have been done before, although systems are known in which a script annotation plane allows users to overlay existing ASCII documents with script comments.
ASCII text editing systems have typically been character-based, using a cursor to control positioning. Script, by its nature, makes character-based editing very difficult. A cursor is not needed with script because of the direct referencing characteristics of a pen. A system that mixes both script and ASCII text must be able to handle the character nature of ASCII as well as the free-form nature of script.
Script is composed of strokes--pen movements captured as the stylus traces a character outline on a digitizing tablet. A script character can contain one or more strokes. Each stroke must be captured and its characteristics maintained in a stroke database. The typical method for this is called the time-order method. The time-order method has limitations, however. This method can lead to misinterpreted characters, depending on how the characters are created. Accordingly, a new approach is required which would eliminate the ordering of strokes merely by the point in time in which they are created.
Another drawback to current art for capturing pen-based stroke data input is the inability of current systems to wrap words and maintain predesignated spacing between words that have wrapped on to a subsequent line. This causes a loss of the user's writing characteristics, resulting in material that is less readable to the person who wrote it. Accordingly, a method is required to maintain predesignated space between words after word wrapping to successive lines occurs.
A system could determine the amount of space between script words by monitoring stroke data input in real time; analyzing the data using pattern recognition techniques, and accordingly developing a method for identifying word separation space. This, however, requires complex software and hardware capability beyond that of the typical pen-based technology commercially available. Accordingly, a method is required which reliably captures word spacing without complex computer analysis of stroke data.
Bit-mapped images, such as those produced by scanners or facsimiles, also create unique problems for pen-based computers. Current pattern recognition techniques convert the bit-mapped image into ASCII text. Once in the ASCII format, however, there is no practical method of incorporating script into the converted document. The ability to combine both ASCII and script in a bit-mapped image is highly desirable. For example, revisions could simply be made on a received FAX image and "FAXed" back to the originator of the FAX. This method would allow revisions to be made electronically to the FAX image without requiring a hardcopy of the FAX.
Accordingly, a need remains for a better way to enter, store, manage and edit handwritten script, or preferably script and binary-encoded text, in a pen-based computer system, and moreover a need remains for a way to combine script and bit-mapped documents.